There are well known in the art methods for pyrolytic, or heat processing of pulverized solid fuels by which both usable products, including solid as well as liquid products, and low-grade products, such as heavy tars and pyrogenic water are produced.
Though the heat of combustion of heavy tars, on the order of 8400 kcal/kg, is known to be higher than that of the product being produced (whose heat of combustion is 6400-6700 kcal/kg), the utilization thereof presents a severe problem. This problem derives from the fact that under normal conditions tar is a sticky viscous substance which is neither sufficiently fluid to be delivered through pipelines nor sufficiently solid to be loaded into and delivered by transporting facilities to the consumer. Consequently, when heavy tar is used as a liquid boiler fuel, it is necessary to transform it into a liquid by heating, which naturally requires additional capital and operating expenses. Yet here, too, the problem of delivering heavy tars to the consumer stands.
Thus, due to heat processing of fuel, the product whose heat of combustion is 8400 kcal/kg practically cannot be used as fuel.
It is also known that pyrogenic water contains approximately 4.5% phenols dissolved therein which are usable products. However, to separate phenols from pyrogenic water requires a complicated procedure which again requires considerable capital and operating expenses. In addition, after the separation of phenols from pyrogenic water, the latter must be purified prior to disposal into a water pool.
As a consequence of the fact that world's natural energy resources are running thin, processing of large quantities of low-grade fuels is gaining in importance. Specifically, the problem of utilizing heavy tar and pyrogenic water which are low-grade products resulting from heat processing of fuels has become ever more acute.
There is known in the art a method for heat processing pulverized brown coal (USSR Inventor's Certificate No. 335267), comprising a first stage of heating the coal by a gaseous heat carrier in less than one second to a temperature of 200.degree.-500.degree. C. with subsequent separating of the heat carrier from the coal, a second stage of heating the coal by the gaseous heat carrier in less than one second to a temperature of 500.degree.-800.degree. C. at which an intensive thermal decomposition thereof takes place with the formation of a vapour-and-gas suspension consisting of a solid portion and a vapour-and-gas portion, condensing the vapour-and-gas portion to obtain gas and valuable liquid products, and to separate therefrom low-grade products, such as heavy tars and pyrogenic water.
The realization of the above method makes it possible to produce along with other usable products also low-grade products such as heavy tars and pyrogenic water whose utilization presents a problem not yet solved.
The object of the invention is to provide a method for heat processing of pulverized brown coal, which, with the power input equal to that of the conventional methods, ensures the production of a solid product with higher heat combustion.
Another object of the present invention is to provide a method for heat processing of pulverized brown coal, which enables utilization of low-grade products.
One more object of the invention is to provide a method for heat processing pulverized solid fuel, which makes it possible to realize pyrolytic processing of the heavy tar - a product of heat processing of brown coal.
Still another object of the present invention is to provide a method for processing of pulverized brown coal, which ehables utilization of organic substances dissolved in pyrogenic water.